Reach Extension Bug

So basically this current bug I discovered while playing a server called "The Hive". During a pvp match I noticed that my opponent was hit me for a few blocks further than the normal reach blocks and I found that very strange. I did some research and found that is was that the normal Minecraft attacking/reach blocks was increased by three blocks giving it a total on a six block reach rather than the normal three block reach. To test this out I went into a survival world and stood in a flat area with some blocks in hand, from where I stood I placed the blocks down to the maximum blocks I could reach which was a total of six blocks away from where I stood. A screenshot on the bug will be provided